第二学期操作系统考卷Word格式.docx
《第二学期操作系统考卷Word格式.docx》由会员分享，可在线阅读，更多相关《第二学期操作系统考卷Word格式.docx（9页珍藏版）》请在冰豆网上搜索。
turnaroundtimeandthroughput;
meetingdeadlinesandpredictability
2.Ifweuseround-robinschedulealgorithm,thenwhentheprocessrunsoutoftimepiecesitwillturnto③_________.
③blocked;
running;
ready;
suspend;
swap;
deadlock;
exit;
killed
3.④_____________isakindofspecialvariablewhichcanonlybemodifiedbytwooperations:
wait（）andsignal（）.Itcanbeusedtoimplementthecontrolmechanismamongseveralasynchronouslyconcurrentrunningprocesses,including⑤_______________and⑥____________.⑤meanstoshareresourcesexclusively,while⑥appliestocontroltheexecutionorderbetweentwoprocessesinlogic.⑦______________isalsoaspecialdatastructureusedfortheabovecontrolmechanism,whichcombines⑤and⑥togetherinonemodule.The⑧_______________in⑦isusedtoimplementthefunctionof⑥.
④⑤⑥⑦⑧：
scheduling;
class;
process;
mutualexclusion;
semaphore;
controlvariable;
conditionvariable;
monitor,synchronization;
sharedvariable;
procedure;
dispatching
4.The⑨______pagereplacementalgorithmhasBelady’sAnomaly.
⑨LRU;
OPT;
FIFO;
Round-robin
5.A80Gharddisk,eachblocksizeis1K,andeachtableentryneeds4bytes,thenitsFATneed⑩______memoryspace.
⑩100M;
160M;
320M;
480M
6.ThetwobasicfeaturesofanOSare⑪______andsharing.
⑪concurrency;
efficiency;
virtualization;
asynchronism;
convenience
7.TherearefourmainmethodsoftransferringinformationbetweenCPUandI/O,asprogramming（orpolling）,
______,
______,and
______.
spooling;
interrupt;
PCI;
DMA;
SCSI;
USB;
northbridge;
southbridge;
channel;
printerport
8.Acomputerusesthedynamicrelocationscheme.Aprogramis5,000byteslongandisloadedataddress2,400.Thenthebaseregister’svalueshouldbe
______,andthelimitregister’svalueshouldbe
2400;
7400;
5000;
2600
9.WhenwemanagethememorybyusingPagingwithSegmentation.Thevirtualaddressisdividedtothreeparts,as
________,
______andoffset.
segmentnumber;
segmentpartition;
mainbootsection;
pagenumber;
pagefault;
pagerestore;
pageage;
offset;
cache;
TLB;
pointer;
pageframe
10．Diskaccesstimeisconstitutedbythe
anddatatransmissiontime.
scheduletime;
seektime;
sectortime;
rotationallatencytime;
cylindertime
Section2.Selection.Thereare10questions,and2scoresperquestion,intotal20scores.Just1answeriscorrectinthe4selects,pleasechooseitout.
1.Twoprocesses,AandB,eachneedthreerecords,1,2,3,inadatabase.IfAasksforthemintheorder1,2,3,theninwhichorderBasksforthem,deadlockisnotpossible.（）
A.1,2,3B.2,1,3C.3,2,1D.1,3,2
2.Itissurethatthetransition（）isneveroccurringintheprocess’3states.
A.running->
readyB.ready->
waiting
C.running->
waitingD.waiting->
ready
3.Theinitialvalueofasemaphoreis2.Itscurrentvalueis-1now.Thatmeansthereis/are（）processeswaitingforthissemaphore.
A.0B.1C.2D.3
4.Inasingleprocessorsystem,thereare10processesinthesystem,andthenthemostamountofprocessintherunningstateis（）.
A1B8C10D9
5.Letthememoryaccesstimebe100nanosecondsandtheaveragepage-faultservicetimebe8milliseconds.Whatisthemaximumacceptablepage-faultrateforalleffectiveaccesstimeofnomorethan10microseconds?
（）
Note:
1nanosecond=10-9s;
1milliseconds=10-3s;
1microseconds=10-6s
A.0.224%B.0.124%C.1.24%D.2.24%
6.FromthedirectoryandtheFATgivenasfollows,weknowthelastblockofthefilewiseis（）.
FAT
/
1
6
2
3
8
4
9
5
7
Filename
Firstblock
wise
star
A.0B.2C.5D.7
7.Thereare4jobs,arrivedalmostsimultaneouslywiththeorder:
J1J2J3J4.Thoserunningtimearelistedasfollow.
JOB
RUNNINGTIME
J1
10minutes
J2
4minutes
J3
6minutes
J4
2minutes
WhatistheaverageturnaroundtimeforthefourjobsusingRound-Robinschedulingalgorithmwithtimesliceequalsto2minutes?
（）
A.13minutesB.15minutes
C.14minutesD.16minutes
8.Inanewfilesystem,thefree-spaceismanagedusingBitVector.Supposethatblocksizeequals2Kbytesandthedisksizeis8gigabyte.Itiseasytoseethatthebitmapforthediskcontains（）blocks.
A.64B.128C.256D.512
9.InContiguousMemoryAllocationstrategy,theleftover[剩余的；
边角料的]space,afterprogramassignment,iscalled_________fragmentation.
A.externalB.wasteC.internalD.allocated
10.Thereare4processessharing9resources.Fordynamicallyavoiddeadlock,themostnumberofresourcewhicheveryprocesscouldrequestis
A.1B.2C.3D.4
Section3.Answerthefollowingquestions.Thereare4questions,intotal20scores
1（5pts）.Acomputerhassixtapedrives,withnprocessescompetingforthem.Eachprocessmayneedtwodrives.Forwhichvaluesofnisthesystemdeadlockfree?
2（5pts）.Considerthefollowingsegmenttable:
Segment
Base
Length
120
600
2100
18
860
100
Whatarethephysicaladdressesforthefollowinglogicaladdresses?
（a）0,430
（b）1,20
（c）2,64
3（5pts）.Considerthetrafficdeadlockdepictedinthefollowingfigure.
a）Pointoutthatwhichresourcesaremutualexclusion.Whichconditionsareholdandrequesting?
Whichconditionisnon-preemptable?
Whichoneiscirclewaiting?
b）Stateasimplyruleforavoidingdeadlocksinthissystem.
（Here,A,B,C,andDareintersections.）
4（5pts）.Considerthefollowingsnapshotofasystem:
Allocation
Max
Available
A
B
C
D
P1
P2
P3
P4
P5
Answerthefollowingquestionsusingthebanker'
salgorithm:
（a）WhatisthecontentofthematrixNeed?
（b）Isthesysteminasafestate?
（c）IfarequestfromprocessP3arrivesfor（0,2,0,0）,cantherequestbegrantedimmediately?
Section4.Calculations.Thereare4questions,intotal30scores.
1（6pts）.Hereisamulti-programmingsystem,whichhas1processorandtwoIOdevices.Threejobs,calledJ1,J2andJ3,comeatthesametime.J1hashighestpriority,J2hassecondone,andJ3hasthird.Thetimesequencestheyusearelistedasfollows.
J1:
I2（30ms）;
CPU（10ms）;
I1（30ms）;
I2（20ms）
J2:
I1（20ms）;
CPU（20ms）;
I2（40ms）
J3:
CPU（30ms）;
I1（10ms）
Inthesystem,CPUoperationandIOoperation（IO1andIO2）workinparallel,andIO1andIO2arealsoworkingparallel.TheCPUutilizationcanbepreempted,buttheIOoperationcannotbepreempted.
Yourtasksare:
（a）Calculatethetimewhentheyarrivedtilltheyhavefinished.（b）CalculatetheutilizationtimeofCPU.
（c）TheutilizationtimeofIOdevices.
2（7pts）.Supposethatadiskdrivehas200cylinders,numbered0to199.Thedriveiscurrentlyservingarequestatcylinder143,andthepreviousrequestwasatcylinder125.Thequeueofpendingrequests,inFlFOorder,is:
86,147,91,177,94,150,102,175,130.
Startingfromthecurrentheadposition,whatisthetotaldistance（incylinders）thatthediskarmmovestosatisfyallthependingrequestsforeachofthefollowingdisk-schedulingalgorithms?
（a）FCFS（b）SSTF（c）SCAN
3（8pts）.Givenmemorypartitionsof100K,500K,200K,300K,and600K（inorder）,howwouldeachofthefollowingalgorithmsplaceprocessesof202K,407K,126K,and416K（inorder）?
（a）First-fit
（b）Best-fit
（c）Next-fit
（d）Worst-fit
4（9pts）.
AnOSusesrequestpagingsysteminmemorymanagement.Assumethecapacityofthemainmemoryis300byte,whichisdividedinto3frames.TheprocesswillaccessthefollowingLogicaladdressbyteseries:
215,328,160,68,346,132,368,432,660,and767.
（a）Writingdownthepage-referencestringsequence.
（b）AnalyzethepagereplacementsituationandcalculatethepagefaultfrequencywhenLRUandFIFOalgorithmisused
Section5.Program：
Thereare2questions,intotal10scores.
1.Thereisaplateonthetableanditcouldonlycontainonefruit.DadFrankcouldputtheappleonitandmumJessicacouldputtheorangeonit.Buttheydosuchjobsbymutualexclusion.SonTomfetchestheorangeonlyanddaughterAnnefetchesappleonly.Theydoitbymutualexclusion,too.PleasewritedownFrank,Jessica,TomandAnne’sprogramsbyusingdown-upoperatingcorrectly.
Solution:
Semaphoreempty=
apple=0,orange=0;
ProcessFather（）
{
wait（empty）;
put_apple;
;
}
ProcessMather（）
{
put_orange;
ProcessSon（）
get_orange;
signal（empty）;
ProcessDaughter（）
;
get_apple;
2.Diningphilosopher（DP）problemisonepopularinstanceofOS’ssynchronizationproblems.HereistheunfinishedpseudocodeforaDPproblemwithfivephilosophers.Pleasecompleteit.
semaphorechopstick[5]={⑥};
semaphorecoord=4;
ProcessPhilosopher（i）
while
（1）
wait（⑦）;
wait（chopstick[i]）;
wait（⑧）;
升级会员 